Apple introduced an update to QuickTime a few months ago that prevented third-party applications (such as QTConvert, or mov123) from using QuickTime to convert protected MP4 files into RAW audio, which was a shortcut around burning tracks to CD and re-ripping them.
Ironically, this forces users (and third-party applications like the ml_iPod WinAMP plugin) to use Hymn (and FairKeys if you don't have an iPod or Windows) to be able to play tracks bought from the iTunes Music Store on non-Apple devices. The benefit of Hymn, of course, is that you don't need to decode and re-encode files, so there's no loss of quality.